Sulfur recycling system

Abstract

A sulfur recycling system that employs biomass and is constructed to be industrially applicable is provided. The sulfur recycling system using biomass is characterized by comprising: a desulfurization step in which biomass or a biomass treated product is desulfurized to remove a sulfur-containing substance from the biomass or the biomass treated product; a recovery step in which sulfur is recovered from a desulfurization treatment residue generated in the desulfurization step; a processing step in which the recovered sulfur is processed into sulfur for vulcanization; a kneading step in which sulfur for vulcanization and a polymer containing a double bond are kneaded together; and a vulcanization step in which the double bond-containing polymer is vulcanized.

Description

Technical Field

[0001] The present disclosure relates to a sulfur regeneration system. Background Art

[0002] Biomass fuel can be a new energy source to replace fossil fuels. Biomass fuel generally refers to fuel derived from or produced from biomass such as plants or animals, and is expected to reduce CO 2 Among biomass fuels, gas fuel, namely biogas, is a gas obtained by fermentation (methane fermentation) or anaerobic digestion. Biogas is a non-exhaustible renewable resource, and the fuel components in the gas (such as methane) can be directly used or burned to generate electricity, etc. Therefore, biogas is expected to be used as a universal energy source.

[0003] In addition, microalgae such as Euglena can produce lipids in their cells through photosynthesis. By extracting and refining these lipids, biomass fuels can be produced, which is expected to reduce CO 2 .

[0004] In general, the above-mentioned biomass fuel contains sulfur compounds, particularly hydrogen sulfide, due to the raw materials or production process. Since hydrogen sulfide causes adverse effects such as corrosion of peripheral devices, hydrogen sulfide is usually removed before the biomass fuel is used as an energy source (for example, see PTL 1). On the other hand, technologies for inhibiting the production of hydrogen sulfide itself have also been studied. For example, PTL 2 discloses a yeast technology that reduces the hydrogen sulfide production capacity.

[0005] Citation List

[0006] Patent Literature

[0007] PTL 1: JP 2012-101139 A

[0008] PTL 2: JP 2010-246440 A Summary of the invention

[0009] Problem that the invention aims to solve

[0010] Here, it is known that sulfur reacts with polymers containing double bonds to undergo vulcanization reactions. This vulcanization technology has been widely used, especially in the rubber field, to support the development of industry. Sulfur for industrial purposes is mainly produced from hydrogen sulfide, a by-product of crude oil hydrodesulfurization. In other words, sulfur comes from fossil resources. From the perspective of maintaining the earth's environment and achieving a sustainable society, it is crucial to build such a sulfur recycling system.

[0011] However, in this regard, for example, hydrogen sulfide contained in biogas is currently removed as described above. Due to difficulties such as high cost, small recovery amount and unstable yield of recycled raw materials, there has been no special report on the recovery of sulfur from such hydrogen sulfide.

[0012] Therefore, the present disclosure is directed to providing a sulfur recycling system using biomass, which is designed to be industrially applicable.

[0013] Solutions for solving problems

[0014] Main features of the present disclosure for solving the above-mentioned problems are as follows.

[0015] [1] A sulfur recycling system using biomass, comprising:

[0016] A desulfurization process for desulfurizing biomass or biomass processed materials to remove sulfur-containing substances from the biomass or biomass processed materials;

[0017] A recovery step of recovering sulfur from the desulfurization treatment residue generated in the desulfurization step;

[0018] A process for processing the recovered sulfur into vulcanizing sulfur;

[0019] A kneading step of kneading sulfur for vulcanization with a polymer having double bonds; and

[0020] A vulcanization process for vulcanizing a polymer containing double bonds.

[0021] [2] The sulfur regeneration system according to [1], wherein the sulfur-containing substance is selected from hydrogen sulfide and sulfur dioxide.

[0022] [3] The sulfur recycling system according to [1] or [2], wherein the biomass is selected from animal excrement, sewage, food waste and microalgae.

[0023] [4] The sulfur recycling system according to any one of [1] to [3], wherein the desulfurization in the desulfurization step is performed by contacting the biomass or the biomass treated material with a contact medium selected from an adsorbent, a solvent, and bacteria.

[0024] Effects of the Invention

[0025] According to the present disclosure, it is possible to provide a sulfur recycling system using biomass, which is designed to be industrially applicable. DETAILED DESCRIPTION

[0026] Hereinafter, the present disclosure will be described in detail based on embodiments.

[0027] It should be noted that the compounds described in this specification may be partially or entirely derived from fossil resources, biological resources such as plant resources, or renewable resources such as used tires, or they may be derived from a mixture of two or more of fossil resources, biological resources and renewable resources.

[0028] <Sulfur Regeneration System>

[0029] The sulfur recycling system of the present disclosure (hereinafter, sometimes simply referred to as "recycling system") is a sulfur recycling system using biomass. The recycling system of the present disclosure includes a step of desulfurizing biomass or biomass processed materials to remove sulfur-containing substances from the biomass or biomass processed materials (desulfurization step), a step of recovering sulfur from the desulfurization treatment residue generated in the desulfurization step (recovery step), a step of processing the recovered sulfur into sulfur for vulcanization (processing step), a step of kneading the sulfur for vulcanization with a polymer containing double bonds (kneading step); and a step of vulcanizing the polymer containing double bonds (vulcanization step).

[0030] The recycling system disclosed in the present invention can be applied to the rubber field such as tires that need to be vulcanized with sulfur.

[0031] It should be noted that although the present disclosure relates to the regeneration of sulfur, nitrogen-containing substances such as ammonia are also generally produced from the biomass used in the present disclosure. Therefore, in the regeneration system of the present disclosure, nitrogen regeneration can also be performed simultaneously.

[0032] (Recycled raw materials)

[0033] In this specification, "biomass" generally refers to organic resources derived from animals and plants, excluding fossil resources (such as oil, coal and natural gas). Biomass is not particularly limited, and a variety of materials can be used as biomass, including, for example, animal excrement, sewage, food waste, microalgae, black liquor, paper, sawmill residues, wood from construction, inedible parts of crops and forest residues.

[0034] As the raw material for recycling supplied to the recycling system of the present disclosure, biomass itself can be used, or a material obtained by any form of treatment of biomass (hereinafter defined as "biomass treated material" in this specification) can be used, or a combination of these can be used. Here, the above-mentioned treatment preferably refers to a treatment that converts biomass into a form that is more easily utilized.

[0035] For example, as a biomass treatment product, biogas obtained by methane fermentation of biomass such as animal excrement, sewage or food waste can be mentioned. Methane fermentation can be carried out using known methods. Biogas obtained from methane fermentation usually contains sulfur-containing substances, mainly hydrogen sulfide, and methane as a fuel component.

[0036] In addition, as an example of a biomass treatment product, for example, oils produced by microalgae including the genus Euglena can be mentioned. Oils produced by microalgae generally contain sulfur-containing substances, mainly hydrogen sulfide, and oils such as wax esters.

[0037] In the recycling system of the present disclosure, the biomass or biomass processed material used as the raw material (processing object) for recycling may be either a single type or a combination of two or more types.

[0038] (Desulfurization process and recovery process)

[0039] In the recycling system of the present disclosure, the desulfurization step is a step of desulfurizing biomass or biomass processed materials to remove sulfur-containing substances from the biomass or biomass processed materials. In the desulfurization step, desulfurization treatment residue is usually generated.

[0040] The recovery step is a step of recovering sulfur from the desulfurization residue generated in the desulfurization step. In other words, in the recovery step, sulfur is recovered as a single sulfur substance.

[0041] It should be noted that the recycling system of the present disclosure is based on the premise of using biomass or biomass treated materials containing sulfur-containing substances as raw materials for recycling. The sulfur-containing substances present in the biomass or biomass treated materials or the sulfur-containing substances removed in the desulfurization process are not particularly limited as long as they contain sulfur as a constituent element, for example, examples thereof include hydrogen sulfide and sulfur dioxide, etc. The sulfur-containing substances removed in the desulfurization process may be a single substance or a combination of two or more substances.

[0042] The desulfurization means in the desulfurization process is not particularly limited, as long as the sulfur-containing substances can be removed from the recycled raw material (biomass or biomass processed material). As an example, desulfurization can be carried out by contacting the recycled raw material (biomass or biomass processed material) with a contact medium selected from an adsorbent, a solvent and bacteria. These contact media can be used alone or in combination of two or more.

[0043] Hereinafter, the implementation schemes of the desulfurization step and the recovery step will be described in detail for each contact medium used.

[0044] [Adsorbent]

[0045] The adsorbent used as the contact medium may be any adsorbent capable of selectively treating (adsorbing) sulfur-containing substances. Specific examples thereof include iron oxide, zinc ferrite, and zeolite. The adsorbent may be used alone or in combination of two or more.

[0046] As an example, when iron oxide is used as an adsorbent, hydrogen sulfide can be converted to iron sulfide upon contact during the desulfurization process. In this case, the desulfurization residue is equivalent to an adsorbent containing iron sulfide. Subsequently, in the recovery process, the iron sulfide in the desulfurization residue can be reacted with a strong acid to restore the iron sulfide to hydrogen sulfide, and sulfur can be recovered from the hydrogen sulfide using known methods. In addition, in some cases, the sulfur in the desulfurization residue (adsorbent containing iron sulfide) can also contain sulfur in addition to iron sulfide. Sulfur can also be recovered from such an adsorbent containing sulfur using known methods.

[0047] Alternatively, as an example, when zeolite is used as an adsorbent, hydrogen sulfide can be directly physically adsorbed onto the zeolite during the desulfurization process. In this case, the desulfurization residue is equivalent to the adsorbent containing hydrogen sulfide. Subsequently, in the recovery process, the desulfurization residue can be subjected to reduced pressure and high temperature conditions to recover hydrogen sulfide, and sulfur can then be recovered from the hydrogen sulfide using known methods.

[0048] Adsorbents such as iron oxide are advantageous because the sulfur recovery efficiency is relatively high.

[0049] As a method for recovering sulfur from hydrogen sulfide, for example, the Claus process can be mentioned. The Claus process involves recovering sulfur from hydrogen sulfide (H 2 S) to convert one-third of the hydrogen sulfide into sulfur dioxide (SO 2 ), and the heat of reaction is used to purify elemental sulfur. In this method, in order to improve the reaction efficiency, unreacted hydrogen sulfide and sulfur dioxide are subjected to Claus reaction using an alumina catalyst, allowing the recovery of elemental sulfur in a higher amount.

[0050] [Solvent]

[0051] The solvent used as the contact medium can be any solvent capable of selectively treating (absorbing or extracting) sulfur-containing substances. Specific examples thereof include monoethanolamine, diethanolamine, and methyldiethanolamine, etc. The solvent can be used alone or in combination of two or more. In addition, the solvent can be diluted with water and used as an aqueous solution.

[0052] As an example, when monoethanolamine is used as a solvent, the monoethanolamine can absorb hydrogen sulfide when in contact during the desulfurization process. In this case, the desulfurization residue is equivalent to a solvent that has absorbed hydrogen sulfide. Subsequently, in the recovery process, hydrogen sulfide is separated by heating the desulfurization residue, and sulfur can be recovered from hydrogen sulfide using a known method (e.g., the above-mentioned Claus process). The same is true when diethanolamine or methyldiethanolamine is used as a solvent.

[0053] It should be noted that solvents such as monoethanolamine are advantageous because they can be reused as contact media even after they are heated during the recovery process.

[0054] [bacteria]

[0055] The bacteria used as the contact medium may be any bacteria capable of selectively treating sulfur-containing substances. Specific examples thereof include sulfur-oxidizing bacteria, etc. More specifically, the sulfur-oxidizing bacteria disclosed in "Hydrogen Sulfide Removal from Biogas by Sulfur Oxidizing Bacteria under Microaerophilic Environment in the Anaerobic Digester" (Japanese Journal of JSCE G, Vol. 65, No. 2, pp. 104-113, June 2009) by, for example, Takuro Kobayashi et al. may be mentioned. The bacteria may be used alone or in combination of two or more.

[0056] As an example, when sulfur-oxidizing bacteria are used as bacteria, hydrogen sulfide is oxidized upon contact during the desulfurization process to produce sulfur. In this case, the desulfurization residue is equivalent to the bacteria containing sulfur. Subsequently, in the recovery process, a cell lysate containing a surfactant or other reagent can be used to decompose the desulfurization residue, after which the sulfur can be extracted using a solvent, thereby allowing the sulfur to be recovered. Examples of solvents used for extraction include carbon disulfide and toluene, etc.

[0057] It should be noted that bacteria are advantageous because they are relatively cheap to maintain.

[0058] (Processing steps)

[0059] The processing step is a step of processing the recovered sulfur into sulfur for vulcanization. The processing step can adopt a known method. For example, in the processing step, the recovered sulfur (sulfur element) can be dissolved in carbon disulfide, and then heated, quenched, separated, dried, and optionally treated with oil as needed to obtain insoluble sulfur (sulfur for vulcanization).

[0060] (Mixing process)

[0061] The kneading step is a step of kneading the above-mentioned sulfur for vulcanization and the polymer having double bonds.

[0062] Examples of polymers containing double bonds include polymers widely used in rubber fields such as tires. Specific examples of polymers containing double bonds include, for example, natural rubber (NR), butadiene rubber (BR), styrene-butadiene rubber (SBR), isoprene rubber (IR), chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR), halogenated butyl rubber and ethylene propylene diene rubber (EPDM). The polymer containing double bonds can be used alone or in combination of two or more.

[0063] In addition, in the kneading process, in addition to the above-mentioned sulfur for vulcanization and the polymer containing double bonds, various additives such as vulcanization aids such as stearic acid, vulcanization accelerators, vulcanization accelerators such as zinc oxide, antioxidants, oils, softeners, plasticizers and processing aids can be appropriately added and kneaded according to the purpose.

[0064] The kneading method is not particularly limited, and kneading can be performed using a kneading machine such as a roll, an internal mixer, and a Banbury rotor.

[0065] (Vulcanization process)

[0066] The vulcanization step is a step of vulcanizing the double bond-containing polymer kneaded with the vulcanizing sulfur. In this step, the vulcanizing sulfur acts as a vulcanizing agent.

[0067] The vulcanization temperature is not particularly limited, and is generally set to 130° C. or more and 180° C. or less. Furthermore, the vulcanization time is not particularly limited, and is generally set to 5 minutes or more and 120 minutes or less.

[0068] The recycling system of the present disclosure has been described above. Next, several systems related to the present disclosure will be described below.

[0069] <Hydrogen sulfide production prediction system>

[0070] When the recycling system of the present disclosure is industrially applicable, it is assumed that desulfurization is performed using a contact medium selected from an adsorbent, a solvent and bacteria. Since the production of sulfur-containing substances derived from biomass is affected by various factors, its prediction is difficult. So far, since sulfur-containing substances (such as hydrogen sulfide) produced from biomass are either not recycled or simply removed, it is not necessary to accurately predict the production.

[0071] Therefore, in the present specification, a production prediction system for hydrogen sulfide generated from biomass (hereinafter, sometimes referred to as a "production prediction system") is provided.

[0072] The yield prediction system of this embodiment includes the following steps:

[0073] Continuously or periodically monitor data on one or more production indices that affect hydrogen sulfide production;

[0074] Calculate the predicted production of hydrogen sulfide based on the monitoring data of the production index;

[0075] determining when to collect the contact medium based on the calculated predicted production of hydrogen sulfide; and

[0076] Collect the contact medium at a determined time.

[0077] Examples of yield indices include, for example, raw materials, temperature, and humidity.

[0078] In particular, when biogas obtained by methane fermentation is used as a raw material for recycling (biomass or biomass processing material), further examples of the yield index include the amount of animal excrement, the type of animal producing the excrement (pigs, cattle, chickens, sheep, etc.), the temperature of the fermentation tank, the size of the fermentation tank and the oxygen concentration in the fermentation tank.

[0079] Furthermore, when the oil produced by microalgae is used as a raw material for recycling (biomass or biomass processed material), further examples of the yield index include the size of the fermentation tank, the amount of sunlight, and the oxygen concentration.

[0080] It should be noted that the above-mentioned production prediction system can improve the calculation accuracy of the predicted production of hydrogen sulfide by using the accumulated data of the production index.

[0081] In addition, when more than two contact media are used, the yield prediction system may further include a step of determining a collection path for the contact media.

[0082] <Adsorbent Activity Prediction System>

[0083] When the recycling system of the present disclosure is industrially applicable, it is assumed that an adsorbent is used as a contact medium for desulfurization. Since the adsorption capacity of the adsorbent may deteriorate over time, it is necessary to replace the adsorbent at an appropriate time. Otherwise, the sulfur-containing substances (such as hydrogen sulfide) that are not captured (adsorbed) may cause corrosion of peripheral devices such as gas tanks. It is assumed in the present disclosure that the amount of recoverable sulfur-containing substances and the effective use of the adsorbent will also be affected.

[0084] Therefore, in the present specification, an adsorbent activity prediction system (hereinafter, sometimes referred to as “activity prediction system”) is provided.

[0085] The activity prediction system of this embodiment includes the following steps:

[0086] Continuously or periodically monitor data on one or more production indices that affect hydrogen sulfide production;

[0087] Determining the predicted activity (also known as the degree of degradation) of the adsorbent based on the monitoring data of the yield index;

[0088] determining when to collect the adsorbent for use as the contact medium based on the determined predicted activity; and

[0089] The adsorbent is collected at a determined time.

[0090] Examples of yield indices include, for example, raw materials, temperature, and humidity.

[0091] In particular, when biogas obtained by methane fermentation is used as a raw material for recycling (biomass or biomass processing material), further examples of the yield index include the amount of animal excrement, the type of animal producing the excrement (pigs, cattle, chickens, sheep, etc.), the temperature of the fermentation tank, the size of the fermentation tank and the oxygen concentration in the fermentation tank.

[0092] Furthermore, when the oil produced by microalgae is used as a raw material for recycling (biomass or biomass processed material), further examples of the yield index include the size of the fermentation tank, the amount of sunlight, and the oxygen concentration.

[0093] It should be noted that the above-described activity prediction system can improve the accuracy of determining the predicted activity of the adsorbent by using the accumulated data of the yield index.

[0094] In addition, when two or more contact media (adsorbents) are used, the activity prediction system may further include a step of determining a collection path for the contact media.

[0095] <Adsorbent Collection and Transportation System>

[0096] When the recycling system of the present disclosure is industrially applicable, it is assumed that desulfurization is carried out using an adsorbent as a contact medium. In some cases, the absolute amount of the production of sulfur-containing substances (sulfur) obtained from biomass or biomass treatment, especially biogas, is less than the amount of sulfur-containing substances (sulfur) obtained from fossil resources. Therefore, it is necessary to collect sulfur-containing substances obtained from multiple locations or to concentrate them in one location.

[0097] Therefore, in the present specification, a system for collecting and transporting an adsorbent, in particular a used adsorbent (hereinafter sometimes referred to as a “collecting and transporting system”) is provided.

[0098] The collection and transportation system of this embodiment includes the following steps:

[0099] Continuously or periodically monitor the data on the degree of consumption of the adsorbent actually used as contact medium,

[0100] Determining when to collect the adsorbent based on the monitoring data of the depletion and the location of the adsorbent, and

[0101] The adsorbent is collected and transported as used adsorbent at a determined timing.

[0102] Examples of the above-mentioned consumption degree include usage (actual operation) time of the adsorbent and activity of the adsorbent.

[0103] In addition, when two or more contact media (adsorbents) are used, the collection and transportation system may further include a step of determining a collection path for the contact media.

[0104] <Certification system for sulfur compounds derived from biomass>

[0105] When the recycling system of the present disclosure is industrially applicable, it may be necessary to prove whether the sulfur-containing substances removed in the desulfurization process, the sulfur-containing substances or the recovered sulfur (hereinafter, sometimes collectively referred to as "sulfur-based compounds") are derived from biomass.

[0106] Therefore, in this specification, a certification system of sulfur-based compounds derived from biomass (hereinafter, sometimes referred to as "certification system") is provided.

[0107] The certification system of the present embodiment includes means constructed to manage traceability related to sulfur in the sulfur recycling system of the present disclosure and to certify that the substances (raw materials) used are derived from biomass.

[0108] The traceability management related to sulfur can be applied to, for example, sulfur-containing substances removed during the desulfurization process, desulfurization treatment residues after the desulfurization process, or recovered sulfur. In addition, the traceability management related to sulfur can also be performed based on, for example, the isotopic composition ratio of sulfur.

[0109] The above-mentioned certification system is preferably constructed to allow access to the history of managed traceability.

[0110] Industrial Applicability

[0111] According to the present disclosure, it is possible to provide a sulfur recycling system using biomass, which is designed to be industrially applicable.

Claims

1. A sulfur regeneration and utilization system using biomass, comprising: A desulfurization process for desulfurizing biomass or biomass processed materials to remove sulfur-containing substances from the biomass or biomass processed materials; A recovery step of recovering sulfur from the desulfurization residue produced in the desulfurization step; Processing steps for processing recovered sulfur into sulfur for vulcanization; a kneading step of kneading the sulfur for vulcanization with a polymer having double bonds; and A vulcanization step of vulcanizing the double bond-containing polymer.

2. The sulfur regeneration system according to claim 1, wherein the sulfur-containing substance is selected from hydrogen sulfide and sulfur dioxide.

3. The sulfur recycling system according to claim 1 or 2, wherein the biomass is selected from the group consisting of animal excrement, sewage, food waste and microalgae. 4 . The sulfur recycling system according to claim 1 , wherein the desulfurization in the desulfurization step is performed by bringing the biomass or the biomass treated material into contact with a contact medium selected from an adsorbent, a solvent, and bacteria.